The present invention relates to an improved biopsy needle suited for use in a biopsy gun, or for use as a surgical instrument.
Biopsy needles, as part of a biopsy system, are generally used in the medical field to remove tissue, cells or fluids from a body for examination. Known biopsy needles have at least one inner needle (stylet) and an outer needle (cannula). The stylet has a point to enable insertion of the needle into a body, and a recess or notch located near its distal end for receiving a tissue sample. The cannula is displaceably guided on the stylet and has sharp cutting edges. Both the stylet and cannula have a connecting element on their proximal ends to enable connection of the needle to the slides of a biopsy gun. The connecting elements in known biopsy needles generally have included either flanges that cooperate with matching contact surfaces on the slides, or recesses that engage a rib located on a slide wherein both the slide and the rib run along the length of the biopsy needle.
Some prior art biopsy needles have the disadvantage that it is sometimes difficult to insert them into the biopsy gun under sterile conditions. Some prior art biopsy guns require a certain spacing between the connecting elements on the stylet and cannula in order for the biopsy needle to be inserted into the biopsy gun. However, this task of inserting the biopsy needle into the biopsy gun while the connecting elements are maintained in a fixed orientation is difficult because the stylet is generally freely displaceable in the cannula. Therefore, it is generally necessary to align the connecting elements of the biopsy needle, either manually or through use of a separate spacer, prior to insertion into a biopsy gun.
After the biopsy needle is inserted into a biopsy gun, if a spacer clip is used, it is generally necessary to remove the spacer in order to close the lid and operate the biopsy gun. Conventional spacer clips require the molding of a separate spacer. This requirement of a separate molding step adds an additional step in the manufacturing and packaging process thereby increasing the costs to produce the biopsy needle. Moreover, the use of a separate spacer clip may require undue handling of the needle in order to connect and disconnect the spacer clip. Furthermore, some conventional biopsy guns do not permit the option of inserting the needle into a biopsy gun in the uncocked position. By permitting a biopsy needle to be inserted in an uncocked biopsy gun, the proper operation of the needle is checked prior to the gun being fired by moving the inner needle and the outer needle relative to each other during the cocking process. An additional disadvantage of some conventional biopsy needles is that under some conditions, the individual connecting elements slip or rotate relative to the slides they are carried on when inserted in a biopsy gun.
While some prior integrated spacers have addressed many of these problems by fixing the relationship between the hubs and needles, it is believed that some of them achieve these benefits at the expense of creating drag on the hubs during firing. Since these prior integrated spacers require a tight friction fit with the hubs, movement of the hubs within the gun may be compromised. Therefore, a need remains for improved integrated spacers.